The present invention relates to a device for adjusting a clearance of a twin clutch, in which two clutch discs are disposed with an intermediate plate therebetween.
In a known twin clutch, shown in FIG. 7, two clutch disc 3 and 4 are disposed between a flywheel 1 and a pressure plate 2 with an intermediate plate 5 therebetween. These members are of annular shapes and are disposed concentrically to an output shaft 6, respectively. The clutch discs 3 and 4 are provided at the radially outer portions with friction facings 8 and 9, and are connected at radially inner hubs to the output shaft 6, respectively. An engaging-releasing mechanism (not shown), such as a diaphragm spring, is connected to the pressure plate 2. In the engaging operation of the clutch, the mechanism forces the pressure plate 2 so that the pressure plate 2 may press the facings 8 and 9 against the flywheel 1 and the intermediate plate 5.
The intermediate plate 5 is provided with a plurality of outer peripheral projections 15. Each projection 15 is provided with a hole 16 parallel to the output shaft 6. A stopper pin 17 is fitted into the hole 16.
As shown in FIG. 8, each stopper pin 17 is formed by a cylindrical spring member having one axially extending slit, and is elastically compressively fitted into the hole 16. The projections 15 are connected to a flywheel ring 19 through elastic straps 18, so that the intermediate plate 5 may be forced in a clutch disengaging direction D, shown in FIG. 7, by the straps 18. The flywheel ring 19 is integrally formed with the flywheel 1, and is arranged at the opposite side to the flywheel 1 with the projections 15 therebetween. In the illustrated clutch engaged condition, the stopper pins 17 contact the flywheel 1, and an axial space L is formed between each stopper pin 17 and a flywheel ring 19.
According to the above structure, when the pressing force by the pressure plate 2 to the facing 9 is released, the facing 9 moves away from the pressure plate 2 and the intermediate plate 5, and the intermediate plate 5 is moved in the disengaging direction D by the elastic straps 18 to release the pressing force applied against the facing 8, so that the clutch disengages. In this operation, the intermediate plate 5 moved in the direction D stops at a position at which the stopper pins 17 contact the flywheel ring 19, so that the intermediate plate 5 does not move excessively toward the pressure plate 2. Therefore, in the disengaging operation, the intermediate plate 5 is not pressed to the facing 9, and thus, a torque is not transmitted through the intermediate plate 5 and the clutch disc 4 to the output shaft 6.
When the facing 8 wears to some extent after a long use, the position of the intermediate plate 5 in the engaged condition moves toward the flywheel 1. In this case, after the stopper pins 17 contact the flywheel 1, the intermediate plate 5 is further forced by the pressure plate 2, and thus, a sliding occurs between the inner peripheral surfaces of the holes 16 and the stopper pins 17, so that the intermediate plate 5 moves in an engaging direction E with respect to the stopper pins 17.
However, in the above structures, there is a relatively large resistance between the inner surface of the holes 16 and the stopper pins 17 when the intermediate plate 5 moves in accordance with the wear of the facing 8, so that the pressing force applied from the pressure plate 2 through the intermediate plate 5 to the facing 8 is reduced by the above frictional resistance. Therefore, it is difficult to press the facing 8 onto the flywheel 1 by a sufficient force, and thus, it is difficult to transmit a sufficiently large torque from the flywheel 1 to the clutch disc 3.
Further, it is difficult to set or adjust the frictional force between the inner surface of the holes 16 and the stopper pins 17 at an intended value. If the frictional force is too small, there is such a problem that the intermediate plate 5 moves in the disengaging direction D and is pressed to the facing 9 during the disengaging operation, even after the stopper pins 17 contact the flywheel ring 19. If the frictional force is too large, said problem, i.e. the reduction of the pressing force for the facing in the engaging oeration, becomes remarkable.
Accordingly, it is an object of the present invention to provide an improved structure, overcoming the above problem.
According to the present invention, a device for adjusting a clearance of a twin clutch comprises a flywheel; a pressure plate; two clutch discs interposed between the flywheel and the pressure plate; an intermediate plate disposed between the clutch discs; a stopper pin parallel to a clutch engaging and disengaging direction; a stopper spring associated to the intermediate plate for connecting the stopper pin to a radialy outer portion of the intermediate plate; and a support member opposed to the flywheel with the stopper pin therebetween; said stopper spring being so adapted that it allows a movement of the stopper pin toward the support member relatively to the intermediate plate, and prevents a movement of the stopper pin in the opposite direction relatively to the intermediate plate.
According to the above structure, the intermediate plate and the stopper pin is strongly connected together by means of a stopper spring in the clutch disengaging operation, so that the intermediate plate does not move toward the pressure plate after the stopper pin contacts the support member. Therefore, in the disengaging operation, the intermediate plate is not pressed to the facing at the pressure plate side.
When the facings wear, the intermediate plate can move smoothly toward the flywheel, even after the stopper pin contact the flywheel in the engaging operation, and there is not large frictional resistance between the intermediate plate and the stopper pin. Therefore, the pressing force applied by the intermediate plate to the facing is not largely reduced by the resistance, and thus, the facing is pressed to the flywheel by a sufficiently large force.
Other and further objects, features and advantages of the invention will appear more fully from the following description of the preferred embodiments of the invention.